Extraction of volatile hydrocarbons from solid or high boiling point liquid hydrocarbons



Oct. 12, 1937. N. H. FREEMAN 2,095,863

EXTRACTION OF VOLATILE HYDROCARBONS FROM SOLID OR HIGH BOILING POINT LIQUID HYDROCARBONS Filed July 22, 1956 2 Sheets-Sheet 1 INVENTOR NAT HARRIS FREEMAN ATTORNEYS Oct. 12, 1937. N. H. FREEMAN EXTRACTION 0F VOLATILE HYDROCARBONS FROM $01.11) OR HIGH BOILING POINT LIQUID HYDROCARBONS I Filed July 22, 1956 2 Sheets-Sheet 2 INVENflOR NAT HARRIS FREEMAN ATTORNEYS Patented Oct. 12, 1.)37

'l OFFICE EXTRACTION F VOL'ATILE HYDROCAR- BONS FROM SOLID OR HIGH BOILING POINT LIQUID HYDROCARBONS Nat Harris Freeman, London, England Application July 22, 1936, Serial No. 92,033 In Great Britain January 9, 1936 Claims.

This invention relates to the extraction of volatile hydrocarbons from coal, shale and other solid hydrocarbonaceous material or from high boiling point liquid hydrocarbons.

5 The object of the invention is to obtain a higher yield of low boiling hydrocarbons than is obtainable by ordinary methods of distillation.

The process of extraction according to the invention consists in passing the raw material through a series of heated chambers of progressively increasing temperature and in bringing the material into intimate contact in each chamber with a hydrocarbon gas or vapor obtained from a preceding or succeeding stage or from an external source, the. said hydrocarbon vapor or gas being activated by passing it over a heated alkaline hydroxide before it enters the distilling chamber.

In carrying the invention into effect according to the preferred form, the raw hydrocarbon material is fed through a series or" separately heated retorts each of which has a separate reflux condenser a portion of the condensate from which is distributed, with or without gas, to a preceding or succeeding retort unit, and wherein volatile gaseous hydrocarbon is fed into each of the units through a heated activating chamber containing an alkaline hydroxide; whereby the material under treatment in the retorts is subjected to a prolonged contact with activated hydrocarbon 30 gas or vapor with the result that a further extractionof volatile from the raw material is obtained.

The invention will now be more particularly described with reference to the accompanying drawings, in which: 1

Figure l is a diagrammatic elevation partly in section of the vertical series of retorts used for the distilling process together with the necessary accessory devices, certain of the reflux condensers being omitted from the drawings to avoid confusion.

Figure 2 is an enlarged diagrammatic sectional view of one of the activating chambers.

The apparatus shown in the drawings consists of a series of retorts A1, A2 A8, disposed one above the other and supported by bearers within a framework 2 carrying heat insulating brickwork 4 which encloses the retorts. Each of the r-etorts is heated by a gas burner 6, air vents 5 being provided in the brickwork for admission of air to the gas burners. The gas burners 6 are fed individually by pipes I, the supply of gas to each burner being controlled by a separate thermostat B so that the working temperatures of the several retorts are individually controlled. The thermostats B are set so that there is a progressive increase of temperature through the series of retorts each individual retort being hotter than the one just above it.

A vent Zii is provided at the top of the apparatus for carrying away the products of combustion.

The retorts A are flat-bottomed circular chambers having central openings I. A feed hopper I2 is provided for delivering the raw material to the uppermost retort A1 and each retort contains a rotary disc or plate 9 arranged so that the material falls on to this plate when it enters the retort. A series of stationary ploughs or scrapers In depending from the roof of the retort are arranged to feed the material towards the periphery of the plate 9 as the latter rotates so that the material ultimately falls over the edge of the plate 9 on to the bottom of the retort. A series of ploughs or scrapers ll depending from the plate 9 are arranged to progress the material inwards over the bottom of the retort until it falls through the central opening I into the next retort. The plates 9 are carried on a common vertical shaft extending centrally through all the retorts. Conical members l3 are fixed to the central shaft 8 so as to assist in delivering the material to the innermost of the ploughs Hi as it falls through the central opening i. The final material, which consists of coke ash or ball-like lumps, is ejected from the lowermost retort As through a chute 2| to a conveyor or other means for removing it.

Each retort A is fitted with a reflux condenser C which receives volatile material from the retort through a pipe It. 'A quantity of the condensate produced in the condenser is fed by gravity through a pipe l5 into the preceding retort, the excess condensate being carried away through a pipe ll. Each of the condensers is provided with a pipe 2! through which uncondensed vapor may be fed into the preceding retort. A branch pipe 22 is provided in connection with each of the pipes ill for carrying away excess uncondensed gas or vapor. This vapor is led through a scrubber, condenser or the like 59 and thence to storage.

Inserted in each of the pipes 2! for leading gas or vapor into the retort is an activating chamber i6 containing a series of trays Hia filled with an alkaline hydroxide. Each of these chambers is heated by a gas burner ISb or by other heating means which may be controlled by a thermostat (not shown) so as to hold the, activating chamber at substantially the same temperature as the retort into which it delivers activated gas or vapor. A system of baiiles I60 the low boiling hydrocarbons, so that the process is arranged to direct the vapor or gas on to the surface of the material in the trays as it passes through the activating chamber.

The preferred activating material is caustic lime, caustic potash or caustic soda, but other alkaline hydroxides or mixtures of alkaline'hydroxides may be used. 7 In the operation of the process according to the invention, coal, shale or like carbonaceous material in ground condition is fed to the uppermost retort by the hopper I2 and passes progressively through all the retorts so that it is subjected to a distillation treatment at successively increasing temperatures. Thus in the first retort, moisture may be totally or partly driven ofi, the dry material passing into the second retort A2 in which the initial volatile material is driven off. Oil may become evident in the second retort but it does not necessarily become volatile until the material reaches the retort A3. In the succeeding retorts, less volatile products are driven off until the tar products come away and the only remaining part of the raw material left in the final retort As is coke and ash. If any pitch be present in the last retorts A7 or As, it causes the small particles of coke to coalesce and form lumps or balls, in which form the material is ejected from the hopper A8 through the chute 2E.

The material under treatment is spread evenly over the plates 9 and over the bottoms of the retorts so that it is evenly wetted with the condensate from the reflux condensers C, each of which delivers condensate obtained from the product of a preceding retort. The non-condensible gas produced from the retort A2 and delivered to the reflux condenser C passes into the retort A1 through the pipe 2| and assists in drying the material in the retort. The retort A2 receives some gas and oil from the retort A3 through the pipes l5 and 2! and the oil prod not in the retort A2, in passing to the retort A3 through the opening I, is re-evaporated and enters the reflux condenser C of the retort As. Part of the condensed oil of this condenser is delivered to the retort A2 but the surplus is drawn by pipes H to storage. In this way the surplus condensate of the reflux condensers C yield each a different material which may be separately stored. For instance, a naptha product is available from the condensers l9 which receive their volatile through pipes 22, a benzol from the first condenser C and then in succeeding condensers varying grades of condensates with some overlaps, until the tar products come away and the only remaining part of the raw material is coke and ash.

It has been found that the distillation of a hydrocarbon containing high boiling oils in the presence of a hydrocarbon gas or vapor in combination with the process of activating the gas or vapor by the action of an alkaline hydroxide increases the yield of volatile hydrocarbons. Moreover the repeated recycling of the vapor through the condensers progressively separates is a refining as Well as an extracting process. It will be understood that the invention can ao ses be applied to the extraction of light oils from heavy oils as well as from solid hydrocarbons. When the raw material is a liquid, the retorts will be fitted with trays arranged to receive the liquid and to permit it to flow successively over one tray to the next, the liquid in the trays being agitated by stirrers which take the place of the ploughs l0 and II.

Although the activating chambers are shown in Figure 1 as being interposed between the retorts and the pipes 2| which receive gas from the reflux condensers, it is to be understood that the invention is not restricted to the process or apparatus in which the gas delivered to the activating chambers is obtained from the reflux condensers. Gas from any external source may be passed through the activating chambers into the retorts.

I claim:

1. A process for the extraction of liquid hydrocarbons from coal, shale and other solid or liquid hydrocarbons which consists in passing the raw material successively through a series of heated chambers of progressively increasing temperature and in bringing the material into intimate contact in each chamber with a hydrocarbon gas that has been treated by passing it over a heated alkaline hydroxide just before it enters the distilling chamber.

2. A process for the extraction of liquid hydrocarbons from coal, shale and other solid or liquid hydrocarbonaceous material which consists in feeding the raw hydrocarbon material successively into separately heated retorts each of which has a separate reflux condenser a portion of the condensate from which is distributed to an adjacent retort unit, and in feeding volatile gaseous hydrocarbon into each of the units through a heated activating chamber containing an alkaline hydroxide, whereby the material under treatment in the retorts is subjected to a prolonged contact with activated hydrocarbon gas with the result that a further extraction of volatile from the raw material is obtained.

3. A process according to claim 1 wherein the alkaline hydroxide is heated to substantially the same temperature as the retort into which the activating gas is delivered.

4. Apparatus for carrying out a process of character described, comprising a series of retorts equipped with heating means, means for feeding hydrocarbonaceous material through the several retorts in succession, a series of reflux condensers each arranged to receive vapor from a retort and to deliver condensate individually to an adjacent retort, and a series of chambers containing activating material and equipped with heating means, said chambers being connected and arranged to deliver activated gas individually to the retorts.

5. Apparatus as claimed in claim 4 wherein the activating chambers are equipped with trays for the activating material and with baflies for directing the gas on to the surface of the material in the trays as it passes through the activating chambers.

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NAT HARRIS FREEMAN. 

